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High performance, reliability and low technical risk are the key features of Space and Communications two proposed designs for the new Intelsat V series of global communications satellites for the 91-naiton Intelsat organization’s global satellite system for 1979.

Hughes is one of four aerospace companies that submitted proposals last October for development of the new satellites. HAC’s independent proposals call for spin-stabilized and three-axis stabilized spacecraft.

Intelsat owns the global system of Intelsat IV and IV-A telecommunications satellites in orbit over the Atlantic, Pacific, and Indian Oceans. The Communications Satellite Corporation, management service contractor, has evaluated competitive bids for the new series and has forwarded its recommendation to Intelsat for review.

Vice President Albert Wheelon, SCG executive, said the two proposals are completely independent, yet both designs are responsive to Intelsat’s requirements.

“Both the spin-stabilized and body-stabilized configurations use a similar high performance communications payload based on improvements of the technology developed by Hughes,” Dr. Wheelon said.

The proposed spin-stabilized Intelsat V is a direct evolution from the previous IV and IV-A programs and many design choices have been made to preserve this similarity and to minimize risk, he added.

The body-stabilized configuration is a new design, but incorporated flight-proven equipment in design and construction.

“The basic structural, thermal and control system designs are a direct outgrowth of an extensive Hughes-funded internal development program devoted to producing maximum effectiveness and design of a three-axis spacecraft,” Dr. Wheelon said.

Overall, the Intelsat V communications payload is the dominant technical feature of both spacecraft configurations. Forty per cent of the program cost is related to the development and manufacture of the communications hardware, which would use approximately 50 per cent of all the high reliability parts.

“A notable feature of these payloads is the contiguous channel multiplexing concept that permits adjacent channels of the repeater to be multiplexed into the same antenna. This allows use of a single light weight antenna at the standard commercial (4 gHz) frequency for hemispheric and zone transmission,” Dr. Wheelon added.

The following comments were provided by Dick Brandes in response to Jack Fisher’s questions about the three-axis design:

It was a very serious effort. Initially, the only design was Rosen’s spinner. However, Wheelon was persuaded to also submit a 3-axis version that could show substantial growth capability. There was a view that Intelsat was determined to have a 3-axis design. A leading advocate of this approach was Warren Nichols. Steve Pilcher led the technical design, which used a momentum wheel and gyro control system. I believe Mike Houterman was the technical leader on the spinner, after Rosen, of course.

The initial Comsat evaluation had the Hughes spinner and 3-axis versions rated 1-2. However, after a series of re-bids that eliminated Lockheed and TRW, it became clear that the spinner would lose to Ford. The final bid was between the Hughes and Ford 3-axis designs, and Ford won with a price advantage of about $15 million.

This was a serious loss and bitter pill to Hughes. The overt manipulation that were openly revealed, led to demands by Hughes for guarantees of a one bid process on Intelsat VI.